The fight -- which also included Kourtney's ex and the father of her three kids, Scott Disick -- erupted after Corey made comments about corporal discipline for the former couple's 7-year-old daughter, Penelope, which he expressed his support for after the child allegedly scratched her nanny.
"If P scratch me, I’m whipping her a**," Corey told Kourtney while at a family dinner that also included Kris, Scott, Kim Kardashian West and Jonathan Cheban.
During the episode, Kourtney tweeted that re-watching the events gave her "anxiety," before responding to a fan that wrote, "Don't let anyone teach you how to be a mommy!"
"Exactly," wrote the 40-year-old reality star, who later added that Corey's comments were "NOT OK with me and never will be."
"And let's support each other knowing we're doing our best," she tweeted.
Not everyone social media was on Kourtney's side. One social media user wrote, "Not trying to be the parent shamer or a judgy person but you need to get your kids in check now & take it serious now before they older because it only gets worse."
"And in my opinion beating children is not the way to 'get your kids in check,'" Kourtney, who's also mom to 9-year-old Mason and 4-year-old Reign, replied. "When children are hurting or frustrated, the answer is not to physically hurt them."
"But they can hit other people when they are angry and frustrated?" a fan questioned in response.
"They’re children and she was clearly hurting inside so hurting her physically is not going to make anything better," Kourtney, who admitted to being "shocked" by some people's responses, replied. "How do we not know better by now?!"
When another user noted that "kids don't usually listen to words they listen to actions," Kourtney, who declared that "in no way is physical harm OK for us," once again defended her stance.
"So you think physical harm is the only action? That’s sad," she wrote. "Of course there are many consequences which we dealt with, I am very proud of my kids and being a parent isn’t always easy, but we do have consequences that don’t involve physical harm."
On the episode, things ended in a bit of a stalemate, with Corey telling Kourtney that he has no intention to "discipline her kids," but adding later in a confessional that "I can say what I want to say because that's my opinion."